YSF Measurement of the shape of the $\mathrm{b}$ quark fragmentation function using charmed mesons produced inside $\mathrm{b}$ jets from $\mathrm{t\overline{t}}$ decays

Abstract

A first measurement of the $\mathrm{b}$ quark fragmentation function at the LHC is presented. Charmed meson candidates produced via semi-leptonic $\mathrm{t\overline{t}}$ decays ($\mathrm{t} \to \mathrm{b}\mathrm{W} \to$ b-jet $\ell \nu$) are used as a proxy for the parent $\mathrm{B}$ meson. Templates are generated at various values of the fragmentation shape parameter $r_{\mathrm{b}}$, and are fit to the data to measure the value of $r_{\mathrm{b}}$. The final fit result is $r_{\mathrm{b}}=0.855 \pm 0.037\;\mathrm{(stat)} \pm 0.031\;\mathrm{(syst)}$. This is the first measurement of the $\mathrm{b}$ quark fragmentation function within a color rich environment, and is consistent with previous results from $e^+e^-$ colliders.